Direct-attached storage (DAS) refers to a data storage system that is directly attached to a server or workstation. The data capacity and connectivity of the DAS system may be improved through the use of switches or expanders, which enable a large bank of DAS devices to be coupled to multiple servers. The storage resources of the DAS devices are made accessible to servers by configuring zone groups, which control how the expanders route connections through the switch to couple specific servers to specific storage drives. Often, components of the DAS system are implemented as blade devices deployed in a blade enclosure. For example, a single blade enclosure may include several blade servers, storage controllers, and switches, among other components. The blade enclosure can provide a variety of services such as power, cooling, networking, various interconnects, and system management. The DAS system may use the Serial Attached Small Computer System Interface (SAS) protocol for physically connecting and transferring data between the servers and the storage devices. Non-blade server solutions are also possible.
A SAS switch storage network can be configured to provide two or more independent SAS fabrics. In such a configuration, one set of initiators may be coupled through a first SAS fabric to a first storage enclosure and another set of initiators may be coupled through a second SAS fabric to a second storage enclosure. Connections between the initiators and the corresponding SAS fabrics may be made through cabling or, in the case of a blade server, the internal interconnects provided by the blade server. In a customer data-center environment, it is often the case that multiple SAS switches controlling different SAS fabrics are operating within the same geographical area, for example, within the same rack.